There are many known designs of livestock self-feeders commercially available and patented. They typically include a feed reservoir disposed over a trough into which the feed is dropped from the reservoir. The feed used in these feeders is seldom free flowing and tends to clump in the reservoir outlets. To combat this, the feeders include some mechanism by which the self-feeding animals can agitate the feed to unclump it or to unclog the opening to cause the feed to drop from the reservoir into the trough.
Much effort has been directed at developing a self-feeder for hogs in particular. Hogs tend to waste a large amount of feed if given the opportunity by knocking it onto the floor or ground as it exits the feed reservoir or from the feeder trough after it has fallen therein. The agitation devices utilized in these feeders tend to take the form of a rod that is swept from side to side by the hog's snout. Some feed naturally falls on the hog's snout when these devices are used and may then dropped onto the floor by the hog.
It would be desirable to have a hog feeder that provided for a reduced amount of feed waste by the self-feeding hog and that could readily vary the amount of feed provided to the trough below to account for different sized hogs and differing feed rations.